Grease gun dispensing head assembly



1960 E. P. SUNDHOLM 2,923,443

GREASE GUN DISPENSING HEAD ASSEMBLY Filed July 1, 1951 INVENTOR:

ATTORNEYS.

TIP

.:metal ifusing process like spot welding or brazing. the making of the present invention, however, Ldid not 2,923,443" Pa en ed b-2.1.1.9 0

This invention relates toa grease gun dispensinghead assembly which is characterized by a positive displaceuncut action, thereby avoiding air locks .and related difficulties.

The grease gun head construction described in my Patent 2,436,701 issued February 24, 1948,"has .great advantages from the standpointof manufacturing simplicity andweconorny. Such construction .is characterized i-by'the fact that themounting cap and cylinder 'blockare formed @flseparate pieces of metal which are .attached by some Unti know how to adapt this type of head construction for :a positive displacement action. Consequently,this type of head construction/although highly advantageous from the manufacturing standpoint, has been 'subject'to certain operational .difliculties. :dispensed contains entrapped air, .the accumulation .ofuair in the residualvolume-between the end of the dispensing stroke and the outlet check valve may lead to an air lock.

It is therefore the principal object ofthe present invention torimprove ,the grease gunrhead construction as .shown in my Patent 2,436,701 so as to adapt it for a fpositive,displacernentaction while still retainingthe advantages of simplicityand economyof manufacture. Fur- .ather objeetsand advantages willaappear; as the specification proceeds.

The present invention is shown in an illustrative embodiment in the accompanying drawing, in which- Figure 1 is a side elevational view of a grease gun embodying the dispensing head assembly of the present invention; Figure 2 is an enlarged side sectional view of the dispensing head assembly of the grease gun of Figure 1, showing the dispensing plunger at its innermost position after the completion of the dispensing stroke; and Figure 3, a view similar to Figure 2, showing the dispensing plunger as it is being moved outwardly on the return stroke preparatory to another dispensing stroke.

Looking first at Figure 1, there is shown a grease gun G of conventional construction, with the exception of the dispensing head assembly H, which forms the subject of the present invention. Figures 2 and 3 show the details of the dispensing head assembly more clearly than in Figure l. and so these figures will be referred to mainly in the following discussion.

The dispensing head assembly H includes a cap which is adapted for attachment to the front end of the grease gun G, or more specifically for being threadedly received on the forward end of the grease gun container or barrel 11. The front of cap 10 is provided with an opening 12 extending therethrough for the outflow of grease from within grease container 11. A cylinder block 13 extends across the front face or outside of cap 10 and is disposed to completely cover cap opening 12.

Cylinder block 13 and cap 10 are formed of separate piece of metal connected by fused areas, as shown more clearly in Figures 2 and 3. Preferably, one of the fused areas extends around cap opening 12 as indicated at 14.

For example, .ifsthegrease being .outer'. end: ofsfitting Z'Zvand terminates in a. coupling:30..

In the illustration: given, thereis another: fused; areaat 15, the location of which also has a special functio in connection withathe present invention, as will be subsequently described.

Cylinder block 13 is provided with a bore 16 extending inwardly from one. end thereof across cap 10. In accordance with the presentinvention, the axis of bore 16 is inclined inwardly toward cap 10 in the manner shown inxFigures 2vand 3.

Passage 17 extends through the wall of block 13 adjacent cap opening 12 and provides communication between the interior of grease container 11 and the intermediate portion of bore 16.

A plunger rod 18: is. slidably received within bore 16, :the rod. being dimensioned to. extend from the innermost end; of the :bore outwardly beyond the cylinder block. A. :lever arm '19 is pivotally connected at 20 to the projecting end of rod 18, the arm being arranged for actuating the rod. In the illustration given, the forwardend of' lever arm 19 is pivotally connected .to apair of'links21 at 22, which in turn are pivotally connected innermost portion of :the arm is spaced. outwardly from the adjacent-end of said cylinder block when the plunger isextending to the innermost end of :bore 16, as in- "dicated in Figures 1 and 2, the desired spacing being designated by the reference number 24. The specific'purpose ofthis spacing willsubsequently be described;

Cylinder block 713 is also provided with a grease .out-

let passage 25 which communicates with the innermost,

endof'bore 16; 'aWithinpassage 25 there is interposed an-.outlet check valve 26, the check valve in its closed position being as closely adjacent as possible to the Wall .of bore 1:6. Intheillustration given, valve 26 is carried by a greaseldisehargesfitting 27. which is threadedly received within :the enlarged portion 25a of passage 25. ya'lve 26.is.-urged to closed position by spring 28. I A grease applicator part 29. :isdetachably connected-to the With the inward inclination of bore 16, it will be noted that the thickness of the portion of the cylinder block that lies between the front face thereof and the nearest wall of bore 16 progressively increases toward the inner end of the bore. Consequently, the thickest portion is adjacent the inner end of bore 16, which is the position where it is desired to locate outlet passage 25 and check valve 26. As shown in Figure 2, when plunger 18 has reached the bottom of its stroke, there is substantially no residual volume between check valve 26 and plunger 16. This will result in the desired positive displacement action referred to previously.

Since the portion of the cylinder block between the inner end of bore 16 and the outer face of cap 10 is relatively thin, it is desirable to add additional strength at this point by locating fusion area 15 thereat. As shown in Figures 2 and 3, the fusion area 15 is approximately adjacent the innermost end of bore 16, andthis location is preferred for the reason indicated.

To provide an end seal for plunger 18, an O-ring 31 is seated within an annular recess 32 adjacent the outer end of cylinder block 13. This type of seal has been found particularly advantageous in combination with the use of an inclined bore, as previously described.

Grease guns are normally used for many years and during the course of such use the various parts will tend to wear. With the construction of the present invention, however, the wearing of the plunger and the pivotal connection between the plunger and the lever arm is substantially compensated for. By providing for a space, such as space 24, between the innermost portion of lever arm 19 and the outer en d of cylinder block 13, even though the pivotal connection 20 becomes substantially looser, it

will still be possible to drive the plunger 18 completely to the inner end of bore 16. In this connection, it has 'also'beenfonnd desirableito provide the inner cendrof plunger 18 with a conical t'apera's'indicat'ed" at 18a and to provide the inner end of bore 16 with a corresponding conical recess, as indicated at 16a, for snu'gly 'receiving the plunger inner end'. i

While in the foregoing specification this invention has a cap adapted for attachmentto the front end of a grease "gun, said cap having an opening therethroug'h forthezo the innermostlendrofsaidtbore outwardly beyond said 1 outflow of grease, a cylinder block extending across the outside of said cap and covering said opening, the central longitudinal axis of said block being substantially parallel to the outside face of said cap, said cylinder block and cap being formed of separate pieces ofmetal connected by fused areas, said cylinder block having a bore extending inwa'rdlyfrorn one end thereof across said cap and having an axis inclining'inwardly' toward said cap, one

-end of said plunger rod for actuating said plunger rod,

of said fused areas beingadjacent the inner end of said 1 bore, said cap opening communicating with said bone at 30 an intermediate point, a plunger rod slidably received within said bore and dimensioned to extend'from the innermost end of said bore outwardly beyond said cylin- I der block, a lever arm pivotally connected to the outer" 1 said lever arm and said plunger rod being dimensioned and arranged so that the innermost portion ofsaid arm is spaced outwardly from the adjacent end of said cylinder block when said plunger, rod is extending'to the innermost end of said bore, said cylinder block providing 40 a grease outlet passage communicating'with-the innermost endof said bore and extending laterallyf therefrom toward the front face of said block, said outlet passage 1 extending through the thickest portion of said cylinder block that lies between thefront face thereof and the gun, said cap having an opening therethrough for the outflow of grease, a cylinder block extending across the front of said cap and coveringgsaid opening, the central longitudinal axis of said block being substantially parallel to the front face of said cap, said cylinder block andcap being formed ofseparate pieces of metal connected by fused areas, 'said cylinder block havinga bore extending inwardly from one, end thereof across 'said'capand inclining toward, said cap, one of said fused areas being adjacent the inner end of said bore, said cap opening communicating with said bore at an intermediate point, one of said fused areas extending around said cap outlet opening and another of said fused areas being positioned adjacent the inner end of said bore, a:plun'ger rod slidably received within said bore Tdimensioned :tojlextend from said cylinder block when said plunger rod is extending to the innermost end of sa'idtbore, saidcylinder block providing a grease outlet passage extending through "the thickest portion of saidlcylinder block'that lies between the front face thereofand the nearest wallofv said bore, the inner end of said plunger ro'cl having a' conical taper and the inner end of said bore'having a corresponding a conical recess for snugly receiving said plunger rod inner end, and an outlet check valve interposed insaid grease outlet passage within the confines of saidcylinder block.

References Cited in the file of this patent UNITED STATES PATENTS 1 I! 1,725,972 Albertine" Au 27; 1929 2,027,500 Vanderlip Jan. 14, 1936 2,060,297 2 Fox Nov. 10, l936 2,250,758 r 

